How to prepare Guyabano or Sour sop tea. (how many leaves per litre)

My mother is not so lucky in genetic lottery hence she is diabetic and I've  noticed that  she has been drinking this tea for some time now and I asked why then she told me that the Guyabano tea was recommended by our elder who had also Diabetes Milletus and passed away comfortably. 

Having heard the story I`ve  researched If it was true.. and boom.. I found out that Guyabano Tea is also a star in this sector of sugar sickness. 

So here`s  how she prepares the tea. (and a common preparation through out the net.)

• Step 1 

 Boil 1 litre of water , then add into the boiling water 15 guyabano leaves (preferably air dried).

• Step 2 

Dont close the lid and continue to boil on low fire for 30 mins until the water drop to approximately 500 ml.

• Step 3

Consume the tea in a 7-8 hour period for at this time the tea is at its most effective. My mom pour the tea into a thermos.

Note: Drink tea 30 mins before meal.